1. Field of the Invention
The invention is concerned with single piece unitary high strength earth working teeth. More particularly it is concerned with such teeth as are useful for penetrating soil and the like. Teeth of this nature are used in a number of earth working machines such as for example scrapers, rippers, excavator buckets, rock buckets and the like. Still more particularly the invention is concerned with teeth which are commonly referred to in the trade as "self-sharpening". Such teeth do not really sharpen themselves as they are used but instead retain a substantially constant or slowly increasing cross section as they wear away so that they are still sharp enough to be useful even after considerable metal has been removed from them during the usual rough usage to which they are subjected.
2. Prior Art
A number of self sharpening teeth are known for use with earth working equipment. Such prior art teeth generally include a proximal end for attachment to an earth working machine and a distal end for penetrating soil. The distal end generally includes, in the prior art teeth, a generally flat trapezoidal member extending from the proximal end of the tooth to form a penetrating portion of the distal end of the tooth. In order to maintain sufficient strength for the tooth, it is customary in such a prior art tooth to provide a pair of ridges one on either side of the generally trapezoidal member, each of the ridges communicating from adjacent the soil penetrating portion of the distal end of the tooth to the proximal end of the tooth. This provides an overall cross section for the ridge containing portion of the distal end of the tooth which comprises the cross section of the trapezoidal member with the cross section of one of the ridges thereatop and the other of the ridges therebelow thus forming a crosslike cross section. The two ridges in such a prior art tooth generally extend at a straight angle or very nearly a straight angle from the proximal end of the tooth. Thus, the trapezoidal member in such teeth can be bisected by a plane passing through the trapezoidal member and through the proximal end of the tooth, said plane being perpendicular to a plane defined by said pair of ridges. Because of the symmetrical nature of such teeth, they do not provide a high penetration angle for the soil penetrating end thereof.
Teeth which are self sharpening and which also allow for the provision of a relatively high penetration angle are also commercially available. For example, H & L Tooth Company of Montebello, California produces a number of commonly designed teeth of this nature. Such teeth generally include a proximal end and a distal end as do the above discussed teeth. The distal end of such teeth, however, generally leave the proximal end thereof at an obtuse angle rather than at approximately a straight angle adjacent a lower portion of the proximal end. Adjacent the upper portion of the proximal end, the distal ends of such teeth generally proceed at substantially a straight angle. Strengthening for such teeth is generally provided by a ridge which is upraised to a point adjacent the earth penetrating end of the distal end of the tooth. The ridge then proceeds towards the proximal end of the tooth and eventually merges therewith. The ridge which supplies rigidity for such teeth is not supported by and does not end adjacent the joining of the proximal end of the tooth with the distal end of the tooth but instead continues well on to an upper portion of the proximal end of the tooth.
An improved unitary high strength earth working tooth which would be self sharpening and which would be highly penetrating while at the same time providing added strength over the existing prior art teeth would be highly desirable. The present invention provides just such an improved tooth.